Next Page: Starts the section on either a left or right page, whichever comes next in the document. If you don’t want your document to include blank pages, choose Next.
Right Page: Starts the section on the first right page. If the next page in your document would be a left-side page, a blank page is inserted before the start of the section on the right.
Left Page: Starts the section on the first left page. If the next page in your document would be a right-side page, a blank page is inserted before the start of the section on the left.
By default (unless you start with a Intro to word-processing and page layout documents in Pages on iPad